Milady Esthetics State Board Practice Test

What occurs when water transitions into ice?

1. It undergoes a chemical change

2. It undergoes a physical change

3. It evaporates

4. It freezes at room temperature

The correct answer is: It undergoes a physical change

When water transitions into ice, it undergoes a physical change. This transformation involves a change in the state of matter from liquid to solid. In this process, the molecules of water lose energy and slow down, leading them to arrange themselves into a structured, solid form known as ice. Physical changes, such as freezing, do not alter the chemical composition of the substance. In this case, the chemical formula of water (H₂O) remains the same when it is in its liquid form or when it solidifies into ice. The key characteristic of a physical change is that it is reversible, as heating the ice will return it to its liquid state without any chemical alteration. Comparatively, a chemical change would involve a transformation that creates new substances through the breaking and forming of bonds. The other choices either mischaracterize the process or inaccurately describe the conditions under which it occurs. Thus, the identification of the transition from water to ice as a physical change is essential in understanding the distinctions between physical and chemical processes.